Friday, August 3, 2012
In my prior post I wrote about the importance of familiarizing ourselves with the flora and fauna of our local native ecosystems. With regard to our native flora, trees make up one of the most important components of any ecosystem. They literally form the foundation of most plant communities and contribute greatly to local animal life.
In my area of Orange County, California, Chino Hills State Park is home to four main tree species, two of which are listed as rare and endangered. First on the list is Coast Live Oak Quercus agrifolia. Known by many as the ‘tree of life’ this type of oak is drought tolerant and evergreen, referred to as ‘live’ oak because of its non-deciduous nature. Coast live oaks have long life spans with some specimens in the park being over 200 years old.
Since my days as a kid, Coast live oaks have always been a welcome site due primarily to the cool shade they provide. Even more importantly are the benefits which these oaks provide for the natural ecosystem they occur within as oak woodland vegetation provides one of the most important habitats for animals.
With the tree's multi-branch habit and propensity to produce snags, oaks provide excellent roosts for raptors as well as nesting cavities for owls, wrens, bluebirds and other bird species. They also support myriad insect species and small mammals which make up critical food ladders. Fallen tree limbs become home for invertebrates as well. Woodlands create favorable environmental conditions by reducing wind and temperature variations compared to surrounding plant communities such as grassland, chaparral, and coastal sage scrub.
A companion to the oak is Sycamore Platanus racemosa, also known locally as ‘Aliso’. The sycamore is one of North America’s largest native broad-leaf trees, and is typically found in riparian plant communities. Unlike other tree species, P. racemosa tends to grow in scattered patterns of individual trees as opposed to typical groupings. Sycamore leaves are very large often reaching ten inches in width. Like Q. agrifolia these trees can live between 250 and 600 years.
It is fairly common to find sycamore trees with hollowed portions in their trunks providing habitat for birds such as the great horned owl. Its large overhanging branches make superb nestling sites for a variety of birds and animals. Historically, Native Americans were known to use sycamore wood to make bowls and other cooking utensils.
Occurring in the dryer chaparral plant community, stands of Tecate Cypress Cupressus forbesii can also be seen. Listed as rare and endangered–and with only four natural populations found in the United States–this tree is one of CHSP's most prized plants! The entire range is found in southern California and northern Baja Mexico.
While Tecate Cypress is adapted to wildfire, it requires a 30 to 60 year fire interval. This time period is consistent with what is naturally required for trees to mature and produce an optimal number of cones. Unfortunately, the frequency of wildfires in its range has radically increased in recent years precluding trees from reaching maturity and producing seed.
On the other hand, efforts by the Irvine Ranch Conservancy and OCCNPS have yielded positive results with regard to maintaining remaining stands in the area, and with continued work the prognosis for the Tecate Cypress is hopeful.
Last and certainly not least, another of Chino Hills State Park’s special habitats is Southern California walnut woodland made up of Juglans californica. This species is considered rare and imperiled, with only about 1500 acres protected. Fortunately several hundred acres of this area occur within Park boundaries.
The original range of Southern California Black Walnut generally occurred from the Santa Clarita River Drainage in Los Angeles County south to the Santa Monica Mountains and east to the Puente-Chino Hills; with an area occurring in the northern part of San Diego County as well. Only scattered pockets remain today with land development the main cause of the walnut woodland’s decline.
These deciduous trees produce walnuts that are used as a food source by animal and bird species such as western gray squirrel, desert wood rat and scrub jay. Wildlife also utilizes its branches and understory vegetation as roosting and nesting sites. Native Americans utilized the walnuts as well.
Native trees are a critical component of any ecosystem. They are the ‘bones’ of the plant community and together with understory shrubs make up the foundation of most naturally occurring ecosystems and native landscapes. Their contribution both aesthetic and utilitarian is one of the true joys of experiencing nature first hand, and one of the best reasons to preserve and plant native species today.